The invention relates generally to hybrid and electric vehicles, and more specifically to systems for charging the energy storage devices used for powering hybrid and electric vehicles.
Hybrid electric vehicles combine an internal combustion engine and an electric motor that is typically powered by an energy storage device, such as a traction battery. Such a combination may increase overall fuel efficiency by enabling the combustion engine and the electric motor to each operate in respective ranges of increased efficiency. Electric motors, for example, may be efficient at accelerating from a standing start, while combustion engines may be efficient during sustained periods of constant engine operation, such as in highway driving. Having an electric motor to boost initial acceleration allows combustion engines in hybrid vehicles to be smaller and more fuel efficient.
Purely electric vehicles typically use stored electrical energy to power an electric motor, which propels the vehicle. Purely electric vehicles may use one or more sources of stored electrical energy. For example, a first source of stored electrical energy may be used to provide longer-lasting energy while a second source of stored electrical energy may be used to provide higher-power energy for, for example, acceleration.
Plug-in hybrid electric vehicles are configured to use electrical energy from an external source to recharge the traction battery. This saves fuel by reducing the amount of time the internal combustion engine must operate to recharge the traction battery. Such vehicles, which may include on-road and off-road vehicles, golf carts, forklifts and utility trucks may use either off-board stationary battery chargers or on-board battery chargers to transfer electrical energy from an external energy source, such as the utility grid, to the vehicle's on-board traction battery. Plug-in hybrid passenger vehicles typically include circuitry and connections to facilitate the recharging of the traction battery from an external energy source, such as the utility grid, for example. Typically, the battery charging circuitry includes boost converters, high-frequency filters, choppers, inductors and other electrical components. These additional components which are not generally used during vehicle operation add cost and weight to the vehicle.
It would therefore be desirable to provide an apparatus to facilitate the transfer of electrical energy from an external source to the on-board electrical storage device of a plug-in vehicle that reduces the number of components dedicated only to transferring energy between the on-board electrical storage device and the external source.